Freezing equipment and method of operating it



FREEZING EQUIPMENT AND METHOD OF OPERATING IT Filgd July 13. 1959 M. G. SHOEMAKER Jan. 8,- 1963 5 Sheets-Sheet 1 AVG.

Jan. 8, 1963 M. s. SHOEMAKER FREEZING EQUIPMENT AND METHOD OF OPERATING IT Filed July 15, 1959 5 Sheets-Sheet 2 M41 (014/ a Maid/4km BY Jan. 8, 1963 M. G. SHO EMAKER 3,071,933

FREEZING EQUIPMENT AND METHOD OF OPERATING IT Filed July 13. 1959 3 Sheets-Sheet 3 INVENTOR.

MAL 6 01 M 6. I/rOI/VAAZ'R Patented Jan. 8, 1963 3,071,933 FREEZING EQUIPMENT AND METHOD OF @IERATING IT Malcolm G. Shoemaker, Doyiestown, Pa., assignor, by mesne assignments, to Philco Corporation, Phiiadel phra, Pa, a corperation of Delaware Filed July 13, 1959, Ser. No. 826,640 2 (Ilaims. (Cl. 62-71) This invention relates to ice making equipment and particularly to an automatic, domestic ice maker wherein a tray, with compartments thereon, is employed for the production of ice blocks. The invention is concerned with means for and a method of filling the ice tray compartments accurately, as well as rapidly, in repeated cycles of a machine of the indicated type. It is a principal object of the invention to provide for this purpose and at.

the same time to construct the entire machine in an efficient, economical and durable way.

Particular objects are: to produce ice blocks rapidly; consistently to produce them in desirable form; to avoid spilling of water; to facilitate ice block harvesting; to avoid freezing of water in supply pipes; to minimize leakage of heat into the freezing zone; and otherwise to improve the ice making means, as will appear from the disclosure which follows.

The filling of the ice tray has been found to be of great importance, in connection with each of the indicated objects, and it has been found possible to improve the system substantially with respect to such filling. At the same time it is possible according to the invention to utilize an ice tray of extremely simple, rugged, and economical design. Improvement has been made by means pro- -viding for certain inclined positions of a suitably formed tray, during the filling operation. Such means will now be described, as utilized in a preferred embodiment of the invention.

In the drawing, FIGURE 1 is a front View, partly broken away, of the preferred embodiment, wherein the ice tray is installed in the freezing compartment of a domestic refrigerator. FIGURE 2 is a detail view, drawn on a larger scale and taken along line 22 in FIGURE 1 after turning the ice tray into a different operative position.

FIGURE 3 is a sectional view, drawn on a still larger scale and taken along line 33 in FIGURE 2. FIG- URES 4 and 5 are similar views, showing further operative positions of the tray. FIGURE 6 is a fragmentary section taken along line 6-6 in FIGURE 5. FIGURE 7 is a schematic representation of the electrical circuit forming part of the apparatus of FIGURE 2. FIGURE 8 is a perspective diagram, schematically showing mechanical linkages and electrical circuits forming part of the apparatus.

FIGURE 1 shows refrigerator 10 with evaporator 11 installed therein, which in turn has ice cube freezing compartment 12 separated from other evaporator portions by vertical partition 13. An upper portion of said freezing compartment contains a structure 14 for the permanent support of a movable and generally flexible ice tray 15, while a stationary basket 16 is removably inserted into a lower portion of said compartment for the storage of ice cubes, made and discharged by said tray.

A single supply pipe or spout 17 is provided, for periodically filling tray with water. As shown in FIGURE 2, a portion of the pipe extends through insulation 18 between outer and inner shells I9, 29 of the refrigerator. In order to prevent freezing of water in pipe 17, outside the refrigerator, and leakage of heat into freezing zone 12, spout '17 is preferably made of heat-insulative material, such as synthetic plastic.

Tray 15 has a series of individual ice block molds or cups 21, formed in a lower portion thereof and separated one from the other by partition walls 22. Said walls extend between lower portions of side walls 23 of the tray and in transverse directions, generally parallel to end walls 24 of the tray. Desirably said lower portion of the tray occupies approximately one-half to three-quarters of the height of the tray.

In accordance with the invention, as indicated in FIG- URES 2 and 3, filling of compartments 21 takes place while the tray is in inclined position. A column 25 of water, coming from spout I7, is directed into one cup 21A of the inclined tray. For admitting the water, a valve 26 is provided in the supply line of said spout, outside of shell 19, and is suitably opened by an electrical solenoid 27, as will be described hereinafter.

Successive positions of a tray according to the invention, which positions occur in any one cycle of operation, are shown by FIGURES 3, 4 and 5. FIGURE 3 shows a filling position of the tray; FIGURE 4 shows the tray properly filled to such extent as is desired and in position for freezing; and FIGURE 5 shows the tray with the frozen liquid disposed therein and about to be removed therefrom. As indicated by FIGURE 3, certain liquid levels and liquid bodies 25A, 25B and 250 are of importance for the new filling operation. When the ultimate liquid level 25C has been reached, with the tray in inclined position, the amount of liquid in the tray is such that when the tray is properly positioned for freezing this liquid (FIGURE 4), top edges 251) of partitions 22 are disposed slightly above and parallel to, the then established liquid level 25F. It is by means of this expedient that formation of individual ice cubes is enforced and that ultimate harvesting thereof (FIGURE 5) is facilitated, although an overlying tray region 2513 (FIGURE 3) is provided for reasons to be explained presently.

When the first ice cube compartment 21A, directly below spout 17 (FIGURE 2), has been filled with water to a first and relatively low level 25A (FIGURE 3), a portion 25B of such water begins to overflow the top edge 25]) of the adjacent partition 22; and such overflowing is relatively rapid, since the cross-section of said liquid portion 258 is relatively compact and deep, as a result of the inclined position of said top edge 25D.

The filling and overflowing continues until all compartments of the tray have been filled to a similar level; and because of the rapidity of the operation, this requires only a very few moments.

Thereafter, during a final part of the filling operation, the tray is filled to a somewhat higher level 25C (FIG URE 3), still safely below the point where a danger of overflowing the top edge of the tray would be incurred; and fill valve 26 (FIGURE 2) is then automatically closed by suitable de-energization of solenoid 27 thereof, as will be described hereinafter.

.It is important that the water internally overflowing in tray 15, from one compartment into another, at once forms a relatively deep body 25B, not a mere film. For this purpose, fairly large angles of inclination or tilt, such as about 25 to 35 degrees (FIGURE 3), are advantageously provided between water level 25A and the general direction of top edge 25]) of partition 22, at least during the filling up to level 25A. If at this time the two lines 25A, 25D were parallel, that is, if both were horizontal, the water supplied by spout 17 would require relatively long intervals of time to build up an appreciable head above each partition edge or weir, and the initial filling of the tray, to level 25A, would take correspondingly longer. In addition, greater difficulty would then be encountered in the attempt so to fill the tray as to establish, in substance, the same ultimate water level 256 in successive filling operations; and there would then be a tendency toward occasional, ultimate formation of an undesirable water body, extending above partitions 22 when the tray is in horizontal position (FIGURE 4).

The immediate formation of a deep, rapidly overflowing body 2513 of water, for the initial filling of the tray to level 25A, is further promoted by providing slight terminal depressions 25E, in line 25D, as shown (FIGURES 3 and 4). Additionally, the use of such depressions in some cases facilitates the fabrication of the tray.

For further enhancement of accuracy in performing the filling operation, valve 26 is provided with means 26A (FIGURE 2) for adjustably predetermining, by suitable fiow control means (not shown), the flow rate of water column 25. Thus it becomes possible, by stopping the filling operation at some suitable moment, to arrange so that the amount of admitted water is just sufficient to fill all compartments 21 to a point below and adjacent level 25D, 25G, pursuant to establishment of the horizontal position of the tray (FIGURE 4).

The arrangement thus far described is effective to make sure that all compartments 21 are properly as well as rapidly filled; and it is effective to insure such filling even in the event that the tray has been subject to some tendency to twist it out of shape incident to the use thereof. Substantial, permanent twisting out of shape is however minimized, not only by the use of a reverse twisting procedure, as will be indicated hereinafter, but additionally by providing tray structures and reinforcements of suitable characteristics as to elasticity and related features, these features being so arranged that weir edges 251) can be twisted, one relative to the other, for ice harvesting, but that they return to a single plane during each filling operation (FIGURES 3 and 5).

An upstanding wall structure 24A (FIGURES S and 6) has therefore been provided, extending around the top of the tray and integrally secured to peripheral-portions of compartments 21. This upstanding wall structure not only affords the required internal overflow zone 25B (FIGURE 3) but also serves to make the top portion of the flexible tray relatively rigid, compared with the lower portion 23A (FIGURE 5). Structure 24A is shown as being further reinforced by a lip 24B, surrounding the entire top portion of the tray. Partition walls 22 can be advantageously constructed in form of bent-over or doubled-up portions 22A of the material from which the tray is fabricated (FIGURE 6), thereby keeping the partitions relatively rigid, particularly in their upper or weir areas 25D, which as indicated must be kept in a somewhat critical correlation to water level 25C (FIGURE 3). Lower portions of these wall elements 22A (FIGURE 6) are relatively readily distorted, incident to the twisting of the end walls 24 relative to one another.

The top of the tray strongly resists distortion, during the flexing operations'applied thereto and allows distortion of the entire tray only about the longitudinal axis of the tray. This characteristic in turn enforces distributed flexing of the lower and more flexible tray portions. In other words, it prevents excessive, localized distortion, for instance of corner portions, while also preventing insuflicient, local distortion. It insures adequate flexing of all compartments, sufiicient to break the bond between ice and tray walls, incident to each twisting action. In addition, the controlled flexing action minimizes the taking of a permanent set.

The rapid and accurate filling of tray compartments 21, by the provision and manipulation of overflow zones 25B, is a primary and very advantageous feature. I-Ieretofore, it has been usual to provide ice trays which the householder was expected to carry from the refrigerator to the kitchen faucet for filling, and then back to the refrigerator. When ice cubes were desired in quantities, the householder had to repeat this performance at various times, which times depended on the temperatures maintained in the refrigerator, incident to the use thereof, and on the type of ice trays. Understandably such operations were more often forgotten than performed; and when they were performed it was not uncommon that water was spilled, inside as well as outside of the refrigerator, causing formation of non-uniform ice blocks, and undesired frost build-up on ice trays or stored goods. In prior automatic fill arrangements, on the other hand, it was diflicult to achieve either accuracy, or rapidity, or spill-proof performance, or economy of construction; and in many instances several or all of these desired features were lacking. In lieu of all this, the invention provides automatic, rapid cycles of accurate filling, freezing and harvesting operations.

In the light of what has been explained it will readily be understood that, pursuant to the admission of water, just filling compartments 21, separate ice blocks are formed, one in each cup 21; this freezing process being applied while the tray is in normal, horizontal position (FIGURE 4). In order to establish this position, the tray is provided with a mechanism (FIGURE 2) which includes a motor 29, for rotating one end 24 of the tray. Also provided is a stop device 30, for limiting rotation of the other end and for thereby flexing the tray.

Certain features of this turning and flexing mechanism are described in copending application Serial No. 802,421, filed on March 27, 1959, by Holland S. Lippincott, under the title Refrigeration Apparatus, which is assigned to the assignee hereof.

An actuator disc or cam unit 34, partly shown in FIG- URE 2 at 34 and more fully although schematically shown by two discs or cams (34 1, 342) in FIGURE 8, is arranged to rotate with tray 15, on a shaft (336) of motor 29. This cam unit is equipped with a system of finger members (343, 344) for engagement with a system of generally stationary witch members (31, 32, 33), said systems being disposed at angularly spaced positions around said shaft and including a tray filling switch (33). This arrangement is more fully indicated in said Lippincott application, as are the following features of it operation.

Initially, when ice cubes have been frozen in tray 15, held in the position of FIGURE 8, a thermostat switch (35) closes. This causes the motor shaft (336) to rotate counter-clockwise as seen from the front of FIGURE 8. The mechanical stop member (30) then cause preflexing of the tray,- whereupon a cam finger member (344) raises the toggle (311) of a reversing switch (31), thereby reversing a motor starting unit (37). Clockwise rotation then takes place wherein tray 15 is resiliently untwisted, turned toward the ice cube harvesting position (FIG- URE 5), reversely twisted, and thereby caused to discharge the ice cubes.

A finger (343) then returns the raised toggle (311) of the reversing switch (31) to lower position. It thereby starts return rotation of tray 15.

An important function of this return rotation is the temporary closure of fill switch 33 by the last-mentioned finger 343. As indicated in FIGURE 8 this fill switch is disposed at an angle to the conventional stop switch member 32 (which controls motor 29 to re-establish in due course the normal, horizontal, freezing position of tray 15). Accordingly the closure of the fill switch occurs before the stopping of motor 29 and when tray 15 is still tilted.

The closure of the fill switch 33 establishes a circuit through closed tray and basket feeler switches 35, 36, energizing solenoid 27 of valve 26 in fill line 17, thereby promptly opening this valve. Thus the tray filling opera tion occurs during completion of the counterclockwise return rotation of the tray. The filling is terminated when the finger 343 overrides the resilient actuating pole 345 of fill switch 33, de-energizing solenoid 27 and allowing self-closing valve 26 to close.

Desirably the rotation is relatively slow, such for intance that the entire cycle of twisting and turning operations lasts about one minute. By this expedient it is possible safely and accurately to perform the filling operation, described above, during part of the return rotation and without any further stopping of the tray. In other words, the tray can be filled within an interval of time during which the tray moves only a relatively small number of degrees, for instance from a 35 degree tilt into and through the position of FIGURE 3 and into a 20 degree tilt. By virtue of the establishment of a deep, rapidly overflowing water body 2513, the entire tray is filled to level 25A within a few moments of this slow rotation; and the final filling up, to a level such as 25C (corresponding to ultimate level 25F, FIGURE 4) can readily be achieved during the final phase of the return rotation. Thereupon the control cam 34, by switch mechanism 32, 33, stops the motor, at the moment when the tray, as already described, has been returned to horizontal position; and in the illustrated embodiment this moment coincides with that of closure of valve 26 (FIGURE 2.).

Ice blocks 28 of uniform size can thus be produced, in desirable configurations, such as those of small rods. They could also be frozen in form of semicylinders, hemispheres or the like.

The process of freezing of water in tray tends to raise the original level 25F (FIGURE 4) to an elevation 25G slightly higher than weir edges 25D, due to expansion of the ice incident to freezing. This, however, causes no freezing together of the ice blocks, which during such expansion already have solid sides, although their cores may still be liquid. As the cups 21 are vertically oriented throughout the freezing process, the ice blocks expand vertically, not laterally. The cubes are accordingly formed as individual bodies, as is usually desired for their normal use in the preparation of drinks and the like or sometimes for the making of smaller flakes or chips of ice.

Also, importantly, the absence of an interconnecting layer of ice between blocks 28 facilitate the automatic harvesting which has been described. The maintenance of uniform conditions in this respect has been found to be necessary wherever automatic harvesting shall be achieved by reasonably low powered equipment, operating at low levels of noise and vibration and constructed simply and economically, a is desired in domestic ice makers.

While only a single embodiment of the invention has been described, it should be understood that the details thereof are not to be construed as limitative of the invention, except insofar as is consistent with the scope of the following claims.

I claim:

1. In the operation of an ice mold having a series of ice block pockets and an undivided overflow space overlying said pockets in said mold: performing a cycle of rotations of the ice mold between an inclined and a level position, for ice block harvesting and ice block freezing respectively; and, prior to completion of rotation of the ice mold from an inclined toward a level position, injecting water into one of said open ice block pockets, for rapid gravitational distribution of such water through the overflow space of the still-inclined mold into the several ice block pockets of the mold.

2. A method of operating an ice tray having a series of open cups formed in the bottom thereof and having an undivided overflow space overlying said cups in the tray, said method comprising: freezing ice blocks in said cups while holding the tray in level position; harvesting the ice blocks while placing the tray in inclined position; returning the tray from inclined position to level position after such harvesting and, during such returning and while the tray is still somewhat inclined, injecting a single jet of water into a single one of said cups for prompt gravitational distribution of such water through said overflow space of the somewhat inclined tray into the other cups.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN THE OPERATION OF AN ICE MOLD HAVING A SERIES OF ICE BLOCK POCKETS AND AN UNDIVIDED OVERFLOW SPACE OVERLYING SAID POCKETS IN SAID MOLD: PERFORMING A CYCLE OF ROTATIONS OF THE ICE MOLD BETWEEN AN INCLINED AND A LEVEL POSITION, FOR ICE BLOCK HARVESTING AND ICE BLOCK FREEZING RESPECTIVELY; AND, PRIOR TO COMPLETION OF ROTATION OF THE ICE MOLD FROM AN INCLINED TOWARD A LEVEL POSITION, INJECTING WATER INTO ONE OF SAID OPEN ICE BLOCK POCKETS, FOR RAPID GRAVITATIONAL DISTRIBUTION OF SUCH WATER THROUGH THE OVERFLOW SPACE OF THE STILL-INCLINED MOLD INTO THE SEVERAL ICE BLOCK POCKETS OF THE MOLD. 